Cemented columbium carbide



Patented Feb. 13, 1934 1.947.200 CEMEN'I'ED cormmrom ricya'c. Kelley, Schenectady, N. Y., assignor .to General Electric Company, a corporation of New York No Drawing. Application February 14, 1931 Serial No. 515,897

2 Claims? The present invention relates to cemented carbide compositions but more particularly to a cemented carbide composition consisting mainly of columbium carbide but containing an appreciable amount of a binder-material havinga lower melting pointthan the carbide.

In my copending application Serial No. 496,826, filed November 19, 1930, I have disclosed a cemented carbide consisting of a mixture of tantac lum carbide and columbiinn carbide with a binder or cementing medium. A tool of this character is particularly adapted for cutting steel, cast iron, hard rubber and like material. I have found however that columbium carbide may be employed'as the main ingredient of a cemented carbide composition, the remainder of the composition consisting of a binder or cementing ma- 'terial having a lower melting point .than the carbide.

In carrying out my invention, columbium carbide is flrst prepared by mixing in a ball mill 187 grams of columbium with 23.6 grams of carbon,

is carried out in a closed graphite tube which is heated in a hydrogen furnace as disclosed in my copending application, Serial No. 308,565, flied September 26, 1928.

The carbide thus produced is-milled for several hours to break it upinto a fine powder capable of passing through a 325 mesh screen. It is then mixed with a suitable powdered binder material which has also been ground to a similar degree "of fineness and which has a lower melting point than the carbide. This mixture is then ground in a ball mill for several hours until it also is capable of passing through a 325 mesh screen,

The powdered material thus formed is placed in a mold and subjected to a pressure of about 30 tons per square inch. The pressed material, which may be handled easily, is then sintered in a closed graphite tube in a hydrogen furnace for about 1 hours. The sintering temperature may vary from about 1300 C. to 1600" C. depending on the binder or cementing material employed in the composition.

The present invention is not limited to any particular cementing material. I may employ various elements of the iron group, e. g. nickel, iron or cobalt either alone or in combination with one another. If' desired, 1 may also employ as the binder material various powdered mixtures consisting of metals of the iron group with metals of the 6th group-of Mendelejefis periodic table of elements. I have employed nickel, iron and cobalt each one taken alone as binder elements for columbium carbide. I have also employed each of these elements in combination with tungsten or molybdenum. When the binder material consists of an element of the iron. group with an element of thefith group, the composition of the binder may vary widely. For example, I have employed binders consisting of a mixture of iron and molybdenum in which the iron has varied from about 10 to about 90% and the molybdenum from 90% to 10%, the lower percentage of iron being associated with the higher percentage of molybdenum and vice verse. I have also employed varying proportions oi. nickel or cobalt with molybdenum or tungsten.

The quantity of binder material employed usually will not comprise more than 13% of the composition. It may however be as high as 25% and as low as 3%, the remainder of the coma position being columbium carbide.

Cemented columbium carbide will cut steel but it is not particularly well adapted for such work. It will however cut in a satisfactory manner materials such as hard rubber or Mycalex, the latter being the trade name of a material consisting of about 40% lead borate and about 60% mica.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. A sintered composition containing about 3% to about 25% of a metallic binder material, the remainder of said composition consisting substantially of columbium carbide, said binder material having a lower melting point than said carbide and consisting mainly of metal of the iron group.

2. A sintered composition containing about 3 to 25% of a binder material, the remainder of said composition consisting of columbium carbide, said binder consisting of about 10% to about of metal of the iron group and about 10% to about 90% of metal of the 6th group of Mendelejefi's, periodic table oi. elements. Y

FLOYD C. 

